Radio-frequency identifier (RFID) methods are widely used for a number of tasks, including smart cards, supporting maintenance tasks, identification badges, tracking objects in manufacturing, retail inventory management, etc. An RFID tag can be attached, e.g., to an inventory object. An RFID apparatus can be configured with an RFID reading device including one or more antennas to read the memory of an RFID tag attached to an inventory object.
The RFID apparatus may be a hand-held device with integrated RFID reading capabilities, can read RFID tags from a range of distances, such as during a retail floor inventory operation. However, one may not know whether all physical structures such as retail floor fixtures (and by extension, all items with attached RFID tags) in a given department have been inventoried. Additionally, it is quite time consuming for the user of an RFID apparatus to perform retail floor inventory multiple times to increase the total number of items included in the inventory.
Further, users typically have no skills for determining an axis of maximum gain, or boresight, for the RFID reading device antenna radiation pattern, which may be affected by the polarization of the one or more antennas in use, and the manner in which the user holds the RFID apparatus. For instance, left-handed use may provide different results than right-handed use, and a one-handed grip may provide different results than a two-handed grip.
Since the RFID reading device antenna radiation pattern is invisible, the user is unable to correlate the motion of the RFID apparatus with the path of the RFID antenna boresight over which RFID tags on the fixtures are read. Further, the motion sensing device frame of reference may not be aligned with the boresight of the RFID reader antenna radiation pattern when the IMU or imaging system has a different boresight than the RFID reader antenna radiation pattern. Thus, the motion path depicted from a sequence of motion sensing device data may not always properly indicate the RFID tag read path of the RFID antenna pattern. The depicted motion path thus may be incorrect and even mislead the user.
Thus, there is needed a way to efficiently and accurately determine the differences in alignment between the motion sensing device frame of reference and the RFID reading device antenna pattern boresight. There is also needed a way to automatically correct time-varying data from a motion sensing device to more accurately depict the path over which RFID tags are read by the RFID apparatus.